The present invention relates to a printing apparatus and power supply load reduction method for a printing apparatus and, more particularly, to a printing apparatus having a plurality of full-line print heads each having a print element array corresponding to the width of a recording medium, and a power supply load reduction method for that printing apparatus.
As an information output device for, e.g., a wordprocessor, personal computer, facsimile apparatus, and the like, a printer that prints information such as desired characters, images, and the like on a sheet-like print medium such as a paper sheet, film, or the like is known.
Various printing schemes for printers are known. Of these schemes, an ink-jet scheme has particularly attracted a lot of attention in recent years since it can print on a print medium such as a paper sheet or the like in a non-contact manner, and can assure low running cost, a simple color structure, low noise due to a non-impact mechanism, and so forth.
Of ink-jet printing apparatuses, a full-line printing apparatus, which has a print head comprising a print element (nozzle) array corresponding to a printing region, and prints while conveying a print medium, is prevalently used since it can achieve a higher-speed print process.
Upon executing a color print process using such full-line printing apparatus, a plurality of print heads that eject different color inks line up in the convey direction of the print medium and are controlled to simultaneously eject inks, thus preventing any printing speed drop even in a color print process.
However, a printing apparatus having a full-line print head requires a power supply capacity that can simultaneously drive all nozzles of the print head since data corresponding to one raster are to be printed simultaneously.
A printing apparatus that achieves a color print process using a plurality of full-line print heads requires a still larger power supply capacity, i.e., a power supply capacity that can drive all nozzles of a plurality of print heads so as to prevent any printing speed drop.
Such increase in power supply capacity results in a large power supply unit size and an increase in manufacturing cost. As a result, the entire printing apparatus becomes bulky, and cost increases.
The present invention has been made in consideration of the above situation, and has as its object to provide a printing apparatus-which can prevent deterioration of image quality and extreme drop of the printing speed without unwantedly increasing the power supply capacity, and a power supply load reduction method for the printing apparatus.
In order to achieve the above object, a printing apparatus of the present invention is a printing apparatus having a plurality of full-line print heads each having a print element array corresponding to a width of a print medium, comprising convey means for conveying the print medium to a position where the print heads can print, print electric power computation means for computing a numerical value that pertains to electric power to be supplied to the print heads upon printing print data when print data that uses a plurality of print media is received, determination means for determining if the numerical value that pertains to the electric power is larger than a predetermined value, distance setting means for setting a distance between the plurality of print media in accordance with the determination by the determination means, and convey control means for controlling the convey means to make the distance between the print media be the distance set by the distance setting means upon conveying the plurality of print media.
Also, in order to achieve the above object, a power supply load reduction method for a printing apparatus of the present invention is a power supply load reduction method for a printing apparatus having a plurality of full-line print heads each having a print element array corresponding to a width of a print medium, comprising the convey step of conveying the print medium to a position where the print heads can print, the print electric power computation step of computing a numerical value that pertains to electric power to be supplied to the print heads upon printing print data when print data that uses a plurality of print media is received, the determination step of determining if the numerical value that pertains to the electric power is larger than a predetermined value, the distance setting step of setting a distance between the plurality of print media in accordance with the determination in the determination step, and the convey control step of controlling the convey step to make the distance between the print media be the distance set in the distance setting step upon conveying the plurality of print media.
More specifically, in a printing apparatus which has a plurality of full-line print heads each having a print element array corresponding to the width of a print medium, upon receiving print data that use a plurality of print media, a print duty or the like as the number of print elements used in a print process with respect to the total number of print elements is computed as a numerical value that pertains to electric power to be supplied to the print heads upon recording the received print data, and the computed value is compared with a predetermined value to determine a distance between neighboring print media, and the print media are controlled to be conveyed at the set print medium distance.
In this way, when a print process is continuously performed on a plurality of print media, electric power required for the print process can become equal to or smaller than an electric power capacity that the power supply equipped in the printing apparatus can supply, by changing the distance between neighboring print media. Hence, the print process on a plurality of print media can be performed while preventing deterioration of image quality and extreme drop of the printing speed without increasing the power supply capacity of the printing apparatus.
For example, when the computed value is larger than the predetermined value, the distance between the neighboring print media is increased so that the numerical value that pertains to electric power becomes equal to or smaller than the predetermined value.
As the numerical value that pertains to the electric power, a ratio of the number of print elements to be driven upon printing the print data to the number of all the print elements of the print heads is preferably used.
The distance setting means selects and sets the distance between the print media from a plurality of pre-set values, thus simplifying processes.
Note that the apparatus preferably further comprises means for changing the predetermined value in correspondence with a size of the print medium and a print region of the print data.
In this case, the apparatus preferably further comprises table creation means for storing the predetermined value corresponding to the size of the print medium and the print region of the print data.
The printing apparatus preferably further comprises memory means for storing the print data in units of pages, and the print electric power computation means computes the numerical value that pertains to the electric power when print data of the next page to be printed is stored in the memory means.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.